Shares of Aldeyra Therapeutics nosedived nearly 70 percent on Wednesday after the U.S. Food and Drug Administration declined to approve the Lexington company’s experimental eye-drop reproxalap. The wipeout erased most of Aldeyra’s market value in a single trading session and sent ALDX to multi-year lows. The company said it received another Complete Response Letter from the FDA.
The FDA decision arrived on the PDUFA target date and, according to Reuters, again left Aldeyra without an approval after regulators questioned whether the drug’s clinical program demonstrated a meaningful symptom benefit. The move capped a review that stretched from late 2025 into March 2026.
A long, fraught review process
Reproxalap has already weathered several rounds with the agency. The FDA issued a Complete Response Letter in November 2023, then followed with another after Aldeyra’s resubmission in April 2025 that flagged what it saw as insufficient evidence of efficacy. Business Wire reported the April 2025 letter, while company disclosures lay out the resubmission timetable and the additional field-trial report the FDA asked Aldeyra to add. The updated material pushed the PDUFA schedule into March 2026, according to SEC filings.
Market reaction
Investors bailed out of ALDX, which closed down roughly 70 percent at about $1.24 on Wednesday in a burst of heavy trading volume, according to market data tracked by StockAnalysis. Local coverage in the Boston Business Journal characterized the rout as coming on what it described as the FDA’s third rejection of the candidate.
Legal fallout
The market shock was quickly followed by a familiar ritual for beaten-up biotechs: outreach from investor-rights law firms. Within hours, shareholder attorneys began soliciting Aldeyra investors, mirroring earlier waves of inquiries that followed prior Complete Response Letters. Notices and previous filings show that lawyers moved fast after those earlier regulatory setbacks, with investor alerts tied to the company’s FDA history circulating shortly after each letter. One set of post-CRL notices and a related securities investigation are outlined in a release from Business Wire.
What’s next for Aldeyra
Aldeyra now faces a tight set of options. It can seek additional meetings with the FDA, design new studies to bolster its symptom data, or shift attention to other assets in its pipeline. Industry coverage has pointed out that an approval could have triggered commercial milestones, including a potential $100 million payment from AbbVie under the companies’ option arrangements, while the latest rejection forces a hard rethink of strategy. The company has said it will review the latest FDA letter and update investors as appropriate, according to Fierce Biotech.
